Method and apparatus for assembling and testing a fluid conduit

ABSTRACT

A method and apparatus for assembling a fluid conduit assembly and testing the fluid conduit for leaks. Clipping devices support fasteners at a position remote from the conduit. According to the invention the fasteners can be loaded into clip nests provided by the clipping devices while leak testing of the conduit is performed. The performance of these steps simultaneously effectively eliminates the conventional requirement of pre-loading installation fasteners into the leak testing apparatus, and thus reduces the overall time required for the testing and assembly of fluid conduits by approximately one third. If the leak test is successful, all of the fasteners are then moved to the conduits and closed to integrate the conduit assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of application Ser. No. 10/752,697,filed Jan. 8, 2004 now U.S. Pat. No. 7,159,450.

FIELD OF THE INVENTION

The present invention relates to production methods and apparatus. Inparticular, this invention relates to a method and apparatus forassembling a fluid conduit assembly and testing the fluid conduit forleaks.

BACKGROUND OF THE INVENTION

Rigid fluid conduits for automobiles, such as brake lines and fuellines, typically must be bent and configured to fit along theundercarriage of an automobile. Such conduits function hydraulically,and must be tested for leaks before being installed, particularly in thecase of brake and fuel systems where failure of the system during usecould be catastrophic to the driver of the automobile.

In the case of fuel lines for example, a conventional leak testingapparatus provides a series of supports positioned to suspend thepre-configured fuel tubes at predetermined intervals during leaktesting. Clips or brackets for fixing the tubes together to create anintegrated fuel line assembly are placed by hand on the conduit supportsin the leak testing apparatus. The clips or brackets also provide a postor other structure for affixing the conduits to the undercarriage of theautomobile. Hereinafter the term “clips” is used to denote closeableclips, brackets and other such fasteners that are used for affixingcomponents such as fuel lines together and/or to an automobile.

The conduits are then positioned in the open clips for leak testing. Totest for leaks the conduits are pressurized by an air compressor, andany detected decrease in pressure will indicate a leak in the conduit.If a leak is detected, one or both of the conduits must be replaced. Ifthere is no leak, the installation clips are closed to secure theconduits together and the fuel line assembly is removed from the leaktesting device and ready to install in an automobile.

However, leak testing is a very delicate and sensitive process, and thefluid conduits must be suspended in a secure and completely motionlessposition in order to ensure that the results of the leak test areaccurate. Accordingly, the tubes are suspended in the leak testingapparatus with the installation clips already installed, so that theclips are ready to be closed when the leak test is complete, to avoidany movement of the tubes during leak testing.

The conventional leak testing/tube clipping procedure thus requires timeto load the clips; additional time to load the tubes into the openclips; additional time to conduct the leak test; and additional time toclose the clips and unload the tube assembly. Due to the sensitivenature of the leak test, the clips cannot be loaded while leak testingis taking place.

SUMMARY OF THE INVENTION

The present invention significantly reduces the time required for theleak testing/tube assembling procedure. According to a preferredembodiment of the invention, at selected intervals along the conduit theleak testing apparatus provides clipping devices which support the clipat a position remote from the conduit. Whereas in prior art systemsclips must be loaded into the leak testing apparatus before the conduitsare suspended for testing, according to the invention the clips can beloaded into clip nests provided by the clipping devices while leaktesting is taking place. If the leak test is successful, all of theclips are then moved to the conduits and closed simultaneously, and thetested tube assembly is then unloaded from the leak testing apparatus.

The invention thus provides a device for the automation of clipplacement and closure, which allows the step of leak testing to becarried out at the same time as the loading of installation clips intothe automated clipping devices. The performance of these stepssimultaneously effectively eliminates the conventional requirement ofpre-loading installation clips into the leak testing apparatus, and thusreduces the overall time required for the testing and assembly of fluidconduits by approximately one third, thereby substantially increasingthe rate of production and commensurately reducing production costs.

The present invention thus provides a method of assembling and testingat least one fluid conduit, comprising the steps of: a. suspending theconduit from a plurality of supports; b. pressurizing the conduit andmonitoring a pressure within the conduit for a preset interval to testfor leaks; c. during step b., loading a closeable fastener to each of aplurality of clip nests respectively supporting the fastener at a firstposition remote from the conduit; d. after the leak test is complete,moving the fasteners to a second position adjacent to the conduit; ande. closing the fasteners.

The present invention further provides a clipping device for applying afastener to a conduit, comprising a clip nest supported at a positionremote from the conduit, an actuator for moving the clip nest toward theconduit, and a conduit clamp for clamping the conduit, actuated bymoving the clip nest toward the conduit, whereby when a fastener isdisposed in the clip nest and the clip nest is moved to a position wherethe fastener is adjacent to the conduit, the clamp bears against theconduit to hold the conduit in the fastener.

The present invention further provides an apparatus for assembling afluid conduit assembly and testing the conduit for leaks, comprising aplurality of supports for suspending the conduit at preset intervals; aleak tester comprising a compressor for pressurizing the conduit to testfor leaks; a plurality of clip nests for respectively supporting aplurality of fasteners at a first position remote from the conduit; andan actuator for moving the fasteners to a second position adjacent tothe conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate by way of example only a preferredembodiment of the invention,

FIG. 1 is a schematic elevational view of a leak testing apparatusaccording to the invention,

FIG. 2 is a perspective view of a preferred embodiment of a clippingdevice for the apparatus of the invention, taken from above and oneside.

FIG. 3 is a perspective view of the embodiment of FIG. 2 taken from thesame side and below.

FIGS. 4A to 4C are schematic side elevations of the embodiment of FIG. 2respectively showing the device infully retracted, partially elevatedand fully elevated positions.

FIG. 5 is a side elevation of the embodiment of FIG. 2 in a fullyretracted position.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a leak testing apparatus 10 according to theinvention. It will be appreciated that the leak testing apparatus 10 canbe used for testing for leaks in any kind of conduit, it beingadvantageously used for pressure-testing automotive conduits such asfuel lines 2. It will be further appreciated that although the leaktesting apparatus of the invention may be used to assemble and test aplurality of conduits 2, it is also useful for testing and assemblingmounting clips to a single conduit.

The leak testing apparatus 10 conventionally comprises an open housing12 with a floor 14 and a series of tube supports 16 positioned along apath conforming to the configuration of the tubes 2, suspending thetubes 2 at a sufficient number of positions to ensure a stable,motionless support for the tubes 2 during the leak testing process. In aconventional leak testing apparatus clips 4 are loaded onto the supports16 prior to loading the tubes 2 into the leak testing apparatus. Thecloseable fasteners, for example clips or brackets 4 will be closed oncethe leak test is successfully completed, to fix the tubes 2 into anintegrated tube assembly and to provide a means (for example a post 4 a)for mounting the tube assembly to an automobile (not shown). Theinvention will be described with reference to the clips 4 illustrated,however it will be appreciated that the invention can be applied equallyto conduits secured by clips, brackets or any other suitable fasteners.

According to the invention, the supports 16 are configured with tubenests, which support the tubes 2 directly, i.e. without first loadingclips 4. The clips 4 are instead loaded onto a plurality of clippingdevices 30 which support the clips 4 in a position remote from the tubes2 until the leak test has been successfully completed, at which pointthe clips 4 are positioned against the tubes 2 and closed to completethe tube assembly. The leak testing apparatus 10 of FIG. 1 is thus usedto perform a preferred embodiment of the method of the invention, whichis as follows:

a. suspending at least one conduit 2 from a plurality of supports 16 ina leak testing apparatus 10;

b. pressurizing the conduit 2 and monitoring a pressure within theconduit 2 for a preset interval to test for leaks,

c. during step b. loading a clip 4 to each of a plurality of clip nests40 respectively supporting the clips 4 at a first position remote fromthe conduit 2;

d. after the leak test is complete, moving the clips 4 to a secondposition adjacent to the conduit 2; and

e. closing the clips 4.

The step of moving the clips 4 to a second position adjacent to theconduit 2 is preferably performed by a clipping device 30 whichautomatically applies the clips 4 to the tubes 2, and preferably closesthe clips 4 as well. FIGS. 2 to 5 illustrate a preferred embodiment of aclipping device 30 for automating the method of the invention in theleak testing apparatus 10 illustrated in FIG. 1.

The clipping device 30 comprises a base 32 supporting a movable clipnest 40, for example comprising a block 41 having a removable insert 43with a depression 42 configured to hold the clip 4 in a stable uprightorientation. The clip 4 shown in the drawings by way of examplecomprises a post 4 a for mounting the clip 4 (and thus the tubeassembly) to the undercarriage of an automobile, and the clip nest 40advantageously has a bottom opening 42 a for receiving the post 4 a,shown in FIG. 4, which helps to keep the clip 4 in position afterloading. However, by forming the insert 43 separately from the block 41,the clip nest 40 can be readily adapted to different clips merely byreplacing the clip insert 43 with an insert of a different configurationadapted to support a different style of clip.

The clip nest 40 is supported on a movable platform 50, which iselevated and retracted by a primary actuator. It will be appreciatedthat this can be any actuator, however in the preferred embodiment thisis advantageously a pneumatic actuator since the leak testing apparatus10 already provides an air compressor 6. In the embodiment shown theprimary actuator comprises a pair of pneumatic pistons 52 extending frompneumatic cylinders 54 formed in the base 32 (shown in FIG. 4B). Theplatform 50 is thus extended from the retracted position shown in FIG.4A to an elevated position as shown in FIG. 4B by pressurizing thecylinders 54, for example through air port 56, and lowered back to theretracted position under the influence of gravity when the air pressureis released. Although a single piston 52 would be sufficient to elevatethe platform 50 to the required level, a pair of pistons 52 is preferredin order to maintain precise alignment between the base 32 and themoving platform 50.

The clip nest 40 thus begins the leak test cycle in the position shownin FIG. 4A, remote from the tubes 2, allowing the operator to load clips4 into the clip nest 40 after the conduits 2 have been affixed to thesupports and while the leak test is being performed. After the leak testis successful, the clip nest 40 is raised to a second position, shown inFIG. 4B, at which the clip 4 is held adjacent to the tubes 2, as will bedescribed in greater detail below.

A tube clamp 70, best seen in FIG. 2, is provided to clamp the tubes 2against the clip 4 when the clip nest 40 is raised to the elevatedposition. In the embodiment shown a clamp arm 72 is pivotally mounted tothe base 32, for example at mounting block 78, and provided with a slot72 a (best seen in FIG. 2) through which a pin or cam 74 is disposed. Abrace arm 76 is fixed to the clamp arm 72. The cam 74 is fixed relativeto the platform 50, as by cam arm 74 a. The brace arm 76 thus pivotsbetween a neutral position removed from the conduits 2 and a clampingposition at which the brace 76 holds the tubes 2 against the clip 4.Elevation of the platform 50 thus causes the cam 74 to travel up theslot 72 a, which is configured and oriented to draw the clamp arm 72toward the base 32 and thus to draw the brace 76 down onto the tubes 2.The tubes 2 are clamped against the clip 4 as the clip nest 40 reachesthe elevated position, as shown in FIG. 4B.

In the preferred embodiment the clipping device 30 also provides meansfor closing the clip 4 after the clip nest 40 has been raised to theelevated position. For this purpose the clip nest 40 is mounted to theplatform 50 by a secondary actuator, in the preferred embodimentcomprising a pneumatic cylinder 60 affixed to the platform 50 anddriving a piston 62 affixed to the clip nest 40. preferably a pair ofguide rods 64 is provided to maintain alignment between the clip nest 40and the platform 50 as the secondary actuator is extended and retracted.

A clip closer 80 comprises a closer arm 82 pivotally mounted to the base32, conveniently to mounting block 78, and provided with respectiveradial and transverse slot sections 82 a, 82 b (best seen in FIG. 3)through which the cam 74 is disposed. A roller arm 84 is fixed to thecloser arm 82 and supports a roller 86 on its free end. The roller 86thus pivots between a neutral position removed from the clip 4 and aclosing position at which the roller 86 rolls along the top portion 4 bof the clip 4 and presses the top portion 4 b onto the body 4 c of theclip to permanently close the clip 4.

The clip closer 80 is not actuated until the conduits 2 are clampedfirmly in place within the clip body 4 b. Elevation of the platform 50causes the cam 74 to travel along the radial slot section 82 a, which isalready oriented generally in the direction of motion of the cam 74 andthis motion therefore does not move the closer arm 82 even while thebrace 76 is being drawn toward the clip 4, as shown in FIG. 4B.

To close the clip 4, the platform 50 is further elevated by the primaryactuator, and at the same time the clip nest 40 is lowered by retractingthe secondary actuator, which thus moves in opposition to the platform50 to maintain the clip 4 in a stationary position adjacent to theconduits 2. During this interval the cam 74 travels along the transverseslot section 82 b, which draws the roller arm 86 sharply toward the clip4 to close the top 4 b of the clip 4, as shown in FIG. 4C.

In operation, a leak testing apparatus 10 such as that illustrated inFIG. 1 is equipped with a plurality of clipping devices 30, one at eachposition where a clip 4 is desired, and a plurality of tube supports 16,positioned so as not to interfere with the clipping devices 30. Apneumatic hose 6 b from a local air compressor 6 is coupled to theprimary and secondary actuators of each clipping device 30. The conduits2 are affixed to the supports 16, and a pneumatic hose 6 a from the aircompressor 6 is coupled to the ends of the tubes 2 in conventionalfashion, as shown in FIG. 1, in preparation for the leak test.

The clipping devices 30 start in the position shown in FIG. 4A, with theprimary actuator fully retracted and the secondary actuator fullyextended. The clamp 70 and closer 80 are in the neutral position, withthe brace 74 and roller 86 spaced well away from the tubes 2 and clip 4,respectively.

The tubes 2 are pressurized to perform the leak test. As the leak testis being performed the operator loads a clip 4 into the clip nest 40 ofeach clipping device 30, oriented such that the top portion 4 a facesthe closer 80. The top portion 4 a of each clip 4 is left fully open.

Upon completion of the leak test, if the test indicates that a tube 2has a leak, the leaking tube 2 is replaced and the test is performedagain. If the test indicates that the tubes 2 are free of leaks, theoperator actuates the primary actuator to elevate the platform 50. Thesecondary actuator is not actuated at this stage, so the clip nest 40remains fixed in position relative to the platform 50. As the pistons 52extend the platform 50 and clip nest 40 are elevated, and the cam 74travels along the slots 72 a and 82 a. The closer arm 82 remainsstationary, but the cam 74 travelling along the slot 72 a draws theclamp arm 72 toward the base 32, and thus draws the brace 74 tightlydown onto the tubes 2 to clamp the tubes 2 against the clip 4, as shownin FIG. 4B.

To close the clip 4, the primary actuator is actuated to further elevatethe platform 50 while the secondary actuator is actuated to retract thepiston 62 into the cylinder 60, and thus lower clip nest 40 toward theplatform 50 as the platform 50 rises. The net result is that the clipnest 40 remains stationary at the level of the tubes 2 while the cam 74travels into the transverse slot 82 b, which draws the roller arm 86sharply toward the clip 4, as shown in FIG. 4C. The roller 86 rollsalong the top 4 b of the clip 4, pressing the top 4 a against the clipbody 4 b and lodging one or more barb-shaped projections into one ormore openings, as is well known, to permanently close the clip 4 overthe tubes 2. The clamp arm 72 is provided with a short radial slotsection 72 b, seen in FIG. 2, which allows the cam 74 to travel throughthe clip closing stage without affecting the position of the clamp 80.

With all clips 4 closed in this fashion, the secondary actuator isextended and the primary actuator is retracted, to return the platform50 and clip nest 40 to the neutral position. The cam 74 travelling backalong the slot 82 b returns the closer 80 to the neutral position, andwith further retraction of the primary actuator the cam 74 travellingback along the slot 72 a returns the clamp 70 to the neutral position torelease the tube assembly from the clipping devices 30. The supports 16are unlatched and the tube assembly is removed from the leak testingapparatus 10. The next set of tubes 2 is positioned in the supports 16,and the process is repeated.

It will be appreciated that making the clip nest 40 movable relative tothe platform 50, and providing the secondary actuator to move the clipnest 40 relative to the platform 50, is for the sole purpose of closingthe clip 4. The aspects of the invention which allow the clips 4 to beloaded while the leak test is being performed, by providing a clip nest40 in a first position remote from the tubes, and after the leak test iscomplete moving the clips 4 into position against the tubes 2, operateequally well whether or not the automatic clip closing system isprovided.

Also, while the drawings illustrate a preferred embodiment in which thetubes 2 are supported above the clipping devices 30, and thus theoperation of the clipping devices 30 is substantially in a verticaldirection, it will be appreciated that since the tubes 2 are held firmlyin place by the supports 16 during the operation of the leak testingapparatus 10, it is not necessary that the “floor” 14 of the leaktesting apparatus be at the bottom. The supports 16 and clipping devices30 can be oriented in any desired fashion, as long as the clips 4 do notdislodge from the clip nests 40 under the influence of gravity.

Various embodiments of the present invention having been thus describedin detail by way of example, it will be apparent to those skilled in theart that variations and modifications may be made without departing fromthe invention. The invention includes all such variations andmodifications as fall within the scope of the appended claims.

1. A clipping device for applying a fastener to a conduit, comprising aclip nest movable from a position remote from the conduit for receivinga fastener to a position adjacent the conduit, an actuator for movingthe clip nest toward the conduit, a conduit clamp for clamping theconduit, actuated by moving the clip nest toward the conduit, wherebywhen the fastener is disposed in the clip nest and the clip nest ismoved to a position where the fastener is adjacent to the conduit, theclamp bears against the conduit to hold the conduit in the fastener, anda fastener closing device comprises a roller arm movable toward thefastener, the roller arm supporting a roller which presses against a topportion of the fastener to close the fastener.
 2. The device of claim 1wherein the actuator is a pneumatic actuator.
 3. The device of claim 1wherein the clip nest is supported on a moving platform by a secondaryactuator, and the fastener closing device is actuated by a cam urgingthe roller arm toward the fastener when the moving platform is movedtoward the conduit, and wherein the clip nest is moved toward the movingplatform to maintain the fastener in a position adjacent to the conduitas the roller arm closes the fastener.